Prior art Christmas lights include a bottom base as illustrated in FIGS. 1 and 2, a light stand 20, and a light bulb 30. Two vertical poles 11 and 12 are projected on the opposite sides of the bottom base 10, and two fasteners 13 and 14 are bent at the inner sides of both vertical poles. Holders 15 and 16 are used to hold a pair of cable wires 18, are formed oppositely between both vertical poles, and facilitate two copper puncture conductors 19 and 19' to connect. A hang hook 17 is placed at a position below the bottom base 10. A light stand 20 is disposed on the bottom base 10. A cable slot 21 is placed under the light stand 20 opposite to the holders 15 and 16 and sockets for the copper conductors 19 and 19' are formed in the light stand 20 (not illustrated). The copper conductors 19 and 19' each has a protruberance 191 and 191' formed on the upper section and a point 192 and 192' at the bottom. One of them is vertically disposed and the other is bent to a flat portion, so as to form a ring contact and a tip contact for an incandescent bulb 30 as it engages within the socket of the light stand 20 (as shown in FIG. 3). The points 192 and 192' of both copper conductors 19 and 19' are installed using a puncturing connection with the pair of electric wires respectively in order to light the bulb 30. As shown in FIGS. 1, 2, and 3, some shortcomings of prior art Christmas lights are outlined as follows: (1) In production, the nicety of the abovementioned Christmas lights habitually used disappears because of manipulation negligence, resulting because the copper conductors may be deformed, the ring contact may become flat or the tip contact may become vertical. Thus, two conditions like that will equally bring about a short circuit. (2) It is impossible to alter lamp holder to another shape for cosmetic purposes.